* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    list-style-type: none;
}

ul {
    display: flex;
    height: 50px;
    background-color: cornflowerblue;
}

ul li {
    display: flex;
    justify-content: center;
    align-items: center;
    flex: 1;
    color: #ffffff;
    font-size: 18px;
}

ul li span {
    cursor: pointer;
    height: 100%;
    line-height: 50px;
    transition: all .5s;
}

ul li span.active {
    border-bottom: 3px solid #c00000;
    color: #c00000;
    border-radius: 2px;
}